Shock wave lithotripsy (SWL) injures renal and nearby tissues in a majority of SWL patients. While the potential long-term consequences of such injury are not known, clinical data suggest that diastolic blood pressure may rise and renal function may fall over the long-term after SWL. These change may be influenced by risk factors that enhance the level of SWL-induced renal trauma. This proposal will identify and characterize those risk factors, particularly as they may lead to acute or chronic impairment of renal hemodynamics and function, permanent alteration of renal structure, and chronic hypertension. The main hypotheses to be tested are 1) that SWL induces acute, but transient, renal injury when renal structure and funtion are normal; and 2) that SWL can cause chronic complications such as an increase in diastolic blood pressure and/or diminished renal function when pre-existing risk factors ar present. The proposed experiments will be conducted in young minipigs using structural, functional and physical measurements and they will focus on the following potential risk factors; number of kidneys, renal infection (pyelonephritis), and unilateral vs bilateral treatment of shock waves. Young pigs provide the model to study the effects of SWL in that the worst-case scenario for maximum renal damage should be realized in their small kidneys compared to those in adults. Animals will receive a clinical dose of shock waves in a Dornier HM3 Lithotripter so that the data will have direct clinical application. Functional parameters to be assessed include glomerular filtration rate, renal blood flow, tubular sodium reabsorption and systemic blood pressure (measured by telemetry). These indices will be compared to morphometric indices of renal structure as assessed by light microscopy, scanning and transmission electron microscopy and 3-D reconstructions. Physical measurements of pressure histories will be determined by a new PVDF pressure transducer. The data collected from these studies will permit the identification of those stone patients who are at risk for acute/chronic complications induced by SWL.